A magnetic recording medium, particularly audio cassette tape, which has recently found increasing utility in radio cassette tape recorder or car stereo must have a high running property and durability at elevated temperature and high humidity. A video cassette tape whose total thickness is 20 .mu.m or less is common. Portable video tape recorders have come into wide use these days. The demand for VTR tape having a running property and durability far beyond those of the conventional tape is great. Needless to say, these audio and video tapes must have improved electromagnetic conversion characteristics such as sensitivity, frequency characteristics, and S/N ratio. Therefore, there exists a great demand for audio and video tapes having running property, durability and electromagnetic conversion characteristics much better than those achieved by the existing product. To meet this demand, several lubricants have been proposed to date, but none of them can meet the demand fully. Two known examples of the conventional lubricant are the combination of a mineral lube oil and aliphatic acid amide (U.S. Pat. No. 3,387,993) and a mineral oil having a melting point of 34.degree. to 54.degree. C. (U.S. Pat. No. 3,525,694). But even these lubricants are not able to provide a magnetic recording medium that meets the current requirement of high running property and durability.